Known ski-lifts employ transportation units comprising disk- or anchor-shaped seats for towing passengers up a slope; and return devices, each comprising a cable fixed at one end to a respective seat.
Such known ski-lift seat return devices normally comprise a supporting structure; a reel mounted to rotate about an axis with respect to the supporting structure; said cable, which is wound about the reel; a spring mechanism connected to the supporting structure and the reel to oppose unwinding of the cable, and to rewind the cable when it is unwound off the reel; and a brake to prevent acceleration and speeding of the reel and cable.
Return devices such as these are known from Austrian Patent No. 389 087 B, German Patent No. 26 36 888 A1, and European Patent No. 0 158 095 A1, in which the brake employs a viscous fluid to exert a brake torque to prevent the reel from speeding. While the above known devices have proved highly effective, such devices have the drawback of the viscous fluid requiring an airtight chamber and being temperature-sensitive, which means the brake torque is also affected by temperature.
Other known return devices feature a brake comprising parts in sliding contact. However, devices of this sort therefore need maintenance to replace the worn contacting parts.